Field of the Invention
The invention relates to an apparatus for regulating the flow of current through a load which is connected to ground via a measurement line. A current is output onto an output line by a device connected to the measurement line which depends on the measured voltage on the measurement line. In a more specific embodiment, the invention relates to an apparatus for regulating the flow of current through a load connected between a positive potential and a first measurement resistor which is connected to ground via a measurement line. A current is output on an output line in dependence on a voltage measured on the measurement line and the output line is connected to a predetermined potential via a second measurement resistor.
German patent DE39 08 558 discloses a signal transmission system in which an analog signal and a digital signal are transmitted to a receiver from a transmitter via a data line. In the receiver, the analog signal and the digital signal are evaluated independently of one another.
German published patent application DE38 26 663 A1 discloses a method and a circuit for simultaneously transmitting operational data, in which operational data and voice signals are transmitted via a line. In that context, the peak values of the operational data are chosen to be higher than the maximum peak values of the voice signals so that the signals can be mixed and the operational data can be recovered from the voice signal using a comparison voltage at the reception location. The voice signal is obtained by subtracting the selected operational data from the mixed signal.
German published patent application DE195 11 140 A1 discloses an apparatus for serial data interchange between two stations via a common data transmission line. The first station recognizes the different bit states on the data line by their different voltage levels. The second station recognizes the different bit states on the data transmission line by the presence or absence of a particular flow of current. The voltage levels are evaluated differently by the stations, so that data can be transmitted in both directions at the same time.
German published patent application DE40 05 813 A1 describes an apparatus for regulating the flow of current through a load. The load is connected in series with a transistor and a measurement resistor. The voltage drop which the load current causes across the measurement resistor is compared with a reference voltage using an operational amplifier. If the voltage drop across the measurement resistor is more than a predetermined value, then an output signal is output which is used to control the load current.